1. Field of the Invention
This invention relates to a vacuum cleaner and, more specifically, to a vacuum cleaner having a dirt detection system.
2. Summary of the Prior Art
Both audio and photo electric dirt sensing are old and well known in the cleaner art. However, audio sensing is deemed preferable since the provision of sensitivity for both fine dirt, i.e., dust, and large particle dirt, i.e., sand, is more easily accommodated in an audio detecting arrangement. Moreover, there is no general accumulation of dirt on an audio sensor since it is not usually disposed in the dust stream so it cannot suffer a distortion or lack of response due to a fine coating of dust such as that to which a photo electric cell is subjected.
Since there is less distortion with an audio detector, the use of an audio sensing system needs utilization of a differing and improved electronic network for final dirt indication so that a more reliable sensing results, in total.
Accordingly, it is an object of the invention to provide an improved electronic dirt sensing circuitry.
It is a further object of the invention to provide an improved electronic dirt sensing circuit for an audio sensing system.
It is a still further object of the invention to provide a dirt sensing circuitry with an improved selectivity arrangement.
It is an additional object of the invention to provide an improved dirt sensing and dirt indicating arrangement utilizable and combined with a vacuum cleaner.